1. Field of the Invention
The present invention relates to a pressure switch, which is applicable for the control of a pressure switch of a small air compressor device, and is capable of fine-tuning the values for configuration and the pressure difference thereof.
2. Description of the Related Art
There are many conventional pressure switches and those incorporating the application of an air compressor are frequently used, which mainly use the principle for the Baton tube or membrane. When the pressure of the compressor is accumulated to a certain predetermined value, the switch will have intermittent actions and stop the air compressor from increasing its pressure. Until the pressure in the air compressor is reduced to a certain predetermined value, the switch will resume its action of continual increase of the pressure. The pressure switch of this sort has a factory default value for a maximum pressure and a minimum pressure, such as 25-35 pounds per square inch (p.s.i.) or 95-105 p.s.i. Therefore, when there is a need for several maximum and minimum pressure differences, we have to buy pressure switches having different predetermined values for the upper limit and lower limit of the pressure, and it is relatively inconvenient and more expensive. The pressure switch of some large air compressors may have the function of fine-tuning the predetermined pressure value and the pressure difference, but its application is too complicated and has a numerous and large lever mechanical structure for the control of the transmission between the pressure source and the switch, and is not applicable for the small air compressors which only allows for very small space for the control between pressure source and the switch.
The objective of this invention is to provide an improved pressure switch which comprises a pressure sensor means for receiving the input pressure and then moving the link rod due to the deformation caused by the input pressure. A contact point fine-tuner having a first contact point is controlled by the link rod and is capable of separating or contacting a second contact point, and the contact point fine-tuner is mounted on a frame that is extended upwards from the pressure sensor means. The link rod of the pressure sensor means has a rotary plate, and such rotary plate comprises a top leaning portion. By adjusting the position of the rotary plate on the link rod, this changes the controlling relation between the first contact point of the contact point fine-tuner to adjust different predetermined pressure values. The contact point fine-tuner has a fine-tuning screw set, which changes the distance between the first contact point and the second contact point by the displacement of the screw set in order to adjust different pressure differences controlled by the pressure switch.